The customary manner of obtaining particulate contamination samples is to lay the sticky side of a tape to the surface that has particulate contamination on it and rub one's finger across the tape so that the particles stick to the tape. It is essential that the finger pressure be as constant as possible so that the same amount of particles will adhere to the length of tape. This of course is almost impossible to perform without varying the finger pressure. The tape is then removed and placed under a microscope where the number and size of the particles can be determined. This is not an optimum method because as the finger is moved across the tape, the amount of pressure will vary, which may cause an inaccurate analysis.
Another device used with the tape lift method for obtaining constant pressure is to roll a solid heavy roller over the tape. The disadvantage of this approach for use in tape lift sampling is that the roller does not conform to the surface imperfections which can cause portions of the particulate contamination samples not to be picked up. In addition, the pressure cannot be varied which may cause an inaccurate sample analysis and may crush the particulate contamination samples.
Accordingly, one object of the invention is to provide a device which will apply constant, predetermined pressure to a surface.
Another object of the invention is to provide a device which will conform to the imperfections of a surface.
A further object of the invention is to provide a device that will insure an accurate sample count using the tape lift method.
Still another object of the invention is to provide a simple device for applying constant pressure to a surface.
A still further object of the invention is to provide a simple device for accurately making a size and count determination of particulate contamination samples using the tape lift method.
Another object of the invention is to provide a constant pressure roller for applying constant pressure to the surface of an adhesive tape that will conform to the imperfections of the surface.